Composite materials formed from a base material together with one or more filler materials are known to be capable of improving properties of the base material. For example, SiO2 (silica) filling is known for improving the thermal conductivity of resin-based semiconductor packaging. Theoretical thermal conductivity coefficients of silica are generally larger than the conventional resin based materials, so a high-density packing of silica filler is one promising approach to obtain such composite materials. As known in the art, the morphology of the filler particles can change the properties of the resulting polymer composite.
Certain materials that can be used as fillers can also provide chemical activity. For example, TiO2 (titania) is known to provide photocatalytic activity. Photocatalytic activity can be enhanced by certain surface processing, such as addition of certain metals on the titania surface. There are some solution-based methods for production of finely dispersed titania having metal on the surface of the particles. However, solution-based methods are generally lengthy multi-step process flows, which form a large amount of wastewater, and may lack sufficient photocatalytic activity and/or stability of photocatalytic activity of the modified titania for certain applications.
What is needed is a new silica comprising filler material that provides significant photocatalytic activity, good catalytic stability, and a simpler process flow for forming the same.